Extract shared adapter validation helpers

tests/test_adapter_support.py

@@ -0,0 +1,106 @@
+import unittest
+
+from dns_sync.adapter_support import (
+    require_action_endpoint,
+    require_desired,
+    require_endpoint_plugin,
+)
+from dns_sync.adapters import (
+    Endpoint,
+    NormalizedObject,
+    PlanAction,
+    PlanOperation,
+)
+
+
+class AdapterSupportTests(unittest.TestCase):
+    def test_endpoint_plugin_accepts_matching_plugin(self):
+        endpoint = Endpoint("npm", "node.example:81")
+
+        require_endpoint_plugin(endpoint, "npm")
+
+
+    def test_endpoint_plugin_rejects_wrong_plugin(self):
+        endpoint = Endpoint("npm", "node.example:81")
+
+        with self.assertRaisesRegex(
+            RuntimeError,
+            "cannot use endpoint",
+        ):
+            require_endpoint_plugin(
+                endpoint,
+                "verizon",
+            )
+
+
+    def test_endpoint_plugin_rejects_empty_expected_name(self):
+        endpoint = Endpoint("npm", "node.example:81")
+
+        with self.assertRaisesRegex(
+            ValueError,
+            "cannot be empty",
+        ):
+            require_endpoint_plugin(endpoint, " ")
+
+
+    def test_action_endpoint_accepts_matching_endpoint(self):
+        endpoint = Endpoint("npm", "node.example:81")
+        action = PlanAction(
+            endpoint_id=endpoint.identity,
+            operation=PlanOperation.CREATE,
+        )
+
+        require_action_endpoint(action, endpoint)
+
+
+    def test_action_endpoint_rejects_other_endpoint(self):
+        endpoint = Endpoint("npm", "node.example:81")
+        action = PlanAction(
+            endpoint_id="npm://other.example:81",
+            operation=PlanOperation.CREATE,
+        )
+
+        with self.assertRaisesRegex(
+            RuntimeError,
+            "does not belong",
+        ):
+            require_action_endpoint(action, endpoint)
+
+
+    def test_require_desired_returns_desired_object(self):
+        desired = NormalizedObject(
+            object_type="example",
+            logical_key="object",
+            payload={},
+        )
+
+        action = PlanAction(
+            endpoint_id="example://endpoint",
+            operation=PlanOperation.CREATE,
+            desired=desired,
+        )
+
+        self.assertIs(
+            require_desired(action),
+            desired,
+        )
+
+
+    def test_require_desired_fails_closed(self):
+        action = PlanAction(
+            endpoint_id="example://endpoint",
+            operation=PlanOperation.CREATE,
+        )
+
+        with self.assertRaisesRegex(
+            RuntimeError,
+            "Test mutation requires desired state",
+        ):
+            require_desired(
+                action,
+                context="Test mutation",
+            )
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_npm_adapter.py

@@ -6,6 +6,7 @@ from dns_sync.adapters import (
     CERTIFICATES,
     PROXY_HOSTS,
     Capability,
+    Endpoint,
     CapabilityOperation,
     NormalizedObject,
     ObjectReference,
@@ -94,6 +95,29 @@ class NpmAdapterTests(unittest.TestCase):
         self.assertIs(adapters[0].client, first_client)
         self.assertIs(adapters[1].client, second_client)
 
+    def test_adapter_rejects_endpoint_for_other_plugin(self):
+        config = self.config()
+        endpoint = Endpoint(
+            "verizon",
+            "192.168.1.1:443",
+        )
+
+        with patch(
+            "dns_sync.plugins.adapters.npm.NpmClient"
+        ) as client_class:
+            with self.assertRaisesRegex(
+                RuntimeError,
+                "cannot use endpoint",
+            ):
+                load_adapter(
+                    "npm",
+                    config,
+                    endpoint,
+                )
+
+        client_class.assert_not_called()
+
+
     def test_capabilities_cover_discovery_apply_and_verify(self):
         adapter = self.adapter(Mock())
 

tests/test_verizon_adapter.py

@@ -5,6 +5,7 @@ from unittest.mock import Mock, patch
 from dns_sync.adapters import (
     DNS_RECORDS,
     Capability,
+    Endpoint,
     CapabilityOperation,
     NormalizedObject,
     PlanAction,
@@ -79,6 +80,32 @@ class VerizonAdapterTests(unittest.TestCase):
             },
         )
 
+    def test_adapter_rejects_endpoint_for_other_plugin(self):
+        config = self.config()
+        endpoint = Endpoint(
+            "npm",
+            "192.168.1.3:81",
+        )
+
+        with patch.dict(
+            os.environ,
+            {
+                "ENABLED_PLUGINS": "npm,verizon",
+                "DNS_SYNC_PLUGIN_PATH": "external_plugins",
+            },
+            clear=False,
+        ):
+            with self.assertRaisesRegex(
+                RuntimeError,
+                "cannot use endpoint",
+            ):
+                load_adapter(
+                    "verizon",
+                    config,
+                    endpoint,
+                )
+
+
     def test_capabilities_cover_dns_discovery_apply_and_verify(self):
         adapter = self.adapter(Mock())
 
@@ -259,7 +286,7 @@ class VerizonAdapterTests(unittest.TestCase):
         with self.assertRaisesRegex(RuntimeError, "cannot discover"):
             adapter.discover("certificates")
 
-        with self.assertRaisesRegex(RuntimeError, "different endpoint"):
+        with self.assertRaisesRegex(RuntimeError, "does not belong"):
             adapter.apply(
                 PlanAction(
                     endpoint_id="verizon://different:443",